Applet Download Incomplete

Question

I'm having a problem with the download of a large applet (approx. 1MB) getting cut short.
Everything appears normal. The Java Extension Installation progress window comes up. But when it tries to run the applet it gets "load: class <className> not found" where <className> is the name of the class in my CODE parameter. It appears that on occasion the download of the jar gets cut off. When I search the browser's cache, I find a jar file that has fewer bytes than it should. In order to initiate a retry, you have to delete the jar file from your browser's cache, close all your browser windows so that the Plug-in with its truncated jar file stops running, and load the HTML page again. It appears that it checks the timestamp of the jar file in your cache and the one on the server and decides that it doesn't need to download it again. But if you delete it from your cache, it forces a retry.
I never have this problem when I open from my hard drive. I've never had the problem with a cable modem connection. I've had it once from a corporate LAN hitting an internet server (i.e., outside corporate WAN). I've had people report the problem with dial-up connections. My theory is that whatever the Plug-in is using to download the applet is more sensitive than either HTTP download or FTP.
I realize that if I used the cache options, once a user has successfully downloaded the applet, there's no more problem. But it makes for a crummy initial user experience if they're unfortunate enough to have their download truncated. Also, given the fact that it doesn't report the download problem and instead says it can't find a class, it makes it look like I'm delivering an untested applet. Not good.
Has anybody else experienced this problem? Is there anything you can do about it? I couldn't find a bug report on it. Is there one?

Answer 1

I get a similar problem which we have diagnosed to be either a network problem (i.e congestion) or a problem with the firewall and bypass proxy settings. The firewall itself slows downloads because the firewall is funnelling connections through it causing a congested network. Our solution (intranet) is to include the correct bypass proxy settings in the browser, though this might not be a very good answer for an internet.
I have one other thing you can make sure you are doing if you are developing your applet locally then moving it to another platform. If you ftp files (like your applet) between machines, especially across different platforms like nt and unix/linex, you might want to verify that you are using binary (and not ascii) transfer to make sure you get all your bytecode. I think if you use another method like remote copy, this is not a problem. I hope this helps.
Rodger